一个最简单的static web server

　　声明：资料来自Tomcat剖析一书，该程序是基于java socket的，socket和stream类作为概念背景，现在仅仅是使用其作为基础类，并不关注其本身，关注点在一个服务器的外部功能和体系结构！

• 代码目录

• HttpServer

package simpleserver;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
/**
 * 说明：   server该服务亲自管理request，和response，当前服务只是一个静态资源服务；
 *         request用来解析请求的数据流，抽象成请求对象
 *         response根据请求路径到根目录寻找资源，并输出；该程序的响应只有响应体
 *
 * 作为一个静态服务器，该程序还需要完善：响应对象本身
 * @author Administrator
 *
 */
public class HttpServer {

    public static final String WEB_ROOT = System.getProperty("user.dir")+File.separator+"webroot";   //指定静态资源目录，请求路径的根目录 

    private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";

    private boolean shutdown = false;

    public static void main(String[]args) {
        System.out.println("打印输出web_root"+WEB_ROOT);
        HttpServer serverSocket = new HttpServer();
        serverSocket.await();  //服务启动
    }

    public void await() {
        ServerSocket serverSocket = null;
        int port = 8080;
        try {
            serverSocket = new ServerSocket(port, 1, InetAddress.getByName("192.168.1.102"));//绑定服务的端口号，连接数量，要连接该服务的地址
        }catch(IOException e) {
            e.printStackTrace();
            System.exit(1);
        }
        while(!shutdown) {
            Socket socket = null;
            InputStream input = null;
            OutputStream output = null;
            try {
                socket = serverSocket.accept();               //1在此监听，阻塞
                input = socket.getInputStream();
                output = socket.getOutputStream();
                Request request = new Request(input);       //2把数据传递给request，令其解析；请求使用socket的输入流
                request.parse();
                Response response = new Response(output);   //3响应对象根据已解析的请求路径，寻找资源；响应使用socket的输出流
                response.setRequest(request);
                response.sendStaticResource();
                socket.close();                                //4发回响应后socket关闭；服务还在
                shutdown = request.getUri().equals(SHUTDOWN_COMMAND);
            }
            catch(Exception e) {
                e.printStackTrace();
                continue;
            }

        }

    }
}

• Request

package simpleserver;

import java.io.IOException;
import java.io.InputStream;
/**
 * @说明：对socket类的inputStream进行解析后生成诸多属性，隶属于该类
 * @author Administrator
 *
 */
public class Request {
    private InputStream input;
    private String uri;

    public Request(InputStream input) {
        this.input = input;
    }

    public String getUri() {
        return uri;
    }

    public void parse() {
        StringBuffer request = new StringBuffer();
        int i;
        byte[]buffer = new  byte[2048];
        try {
            i = input.read(buffer);
        }catch(IOException e) {
            e.printStackTrace();
            i = -1;
        }
        for(int j=0;j<i;j++) {
            request.append((char)buffer[j]);
        }
        System.out.println(request.toString());
        uri = parseUri(request.toString());
        System.out.println("截取出来的路径"+uri);
    }
    private String parseUri(String requestString) { //只解析出请求数据中的uri属性
        int index1, index2;
        index1 = requestString.indexOf(‘ ‘);
        if(index1 != -1){
            index2 = requestString.indexOf(‘ ‘, index1 + 1);
            if(index2 > index1) {
                return requestString.substring(index1+1, index2);
            }
        }
        return null;
    }

}

• Response

package simpleserver;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;

public class Response {
    private static final int BUFFER_SIZE =1024;
    Request request;
    OutputStream output;
    public Response(OutputStream output) {
        this.output = output;
    }
    public void setRequest(Request request) {
        this.request = request;
    }

    public void sendStaticResource() throws IOException{
        byte[] bytes = new byte[BUFFER_SIZE];
        FileInputStream fis = null;
        try {
            File file = new File(HttpServer.WEB_ROOT, request.getUri());    //1根目录拼接请求路径
            System.out.println("请求路径"+file.getAbsolutePath());
            if(file.exists()){
                System.out.println("文件存在");
                fis = new FileInputStream(file);
                int ch = fis.read(bytes, 0, BUFFER_SIZE);
                while(ch!=-1){
                    output.write(bytes, 0, ch);                             //2.1请求的响应数据写入输出流
                    ch = fis.read(bytes, 0, BUFFER_SIZE);
                }
            }
            else {
                String errorMessage = "HTTP/1.1 404 File Not Found\r\n"     //2.2响应数据写入输出流
                        + "Content-Type: text/html\r\n"
                        + "Content-Length: 23\r\n"
                        + "\r\n"
                        + "<h1>File Not Found</h1>";
                output.write(errorMessage.getBytes());
            }
        }catch(Exception e){
            System.out.println(e.toString());
        }finally {
            if(fis!=null){
                fis.close();
            }
        }

    }

}

原文地址：https://www.cnblogs.com/10000miles/p/9211231.html